Human Action: A Treatise on Economics is the magnum opus of the Austrian economist Ludwig von Mises. It presents a case for laissez-faire capitalism based on Mises' praxeology, or rational investigation of human decision-making. It rejects positivism within economics. It defends an a priori epistemology and underpins praxeology with a foundation of methodological individualism and laws of apodictic certainty. Mises argues that the free-market economy not only outdistances any government-planned system, but ultimately serves as the foundation of civilization itself.